CausesBy Mayo Clinic staff
Like any allergy, mold allergy symptoms are triggered by an overly sensitive immune system response. When you inhale tiny, airborne mold spores, your body recognizes them as foreign invaders and develops allergy-causing antibodies to fight them.
After the exposure has passed, you still produce antibodies that "remember" this invader, so that any later contact with the mold causes your immune system to react. This reaction triggers the release of substances such as histamine, which cause itchy, watery eyes, runny nose, sneezing and other mold allergy symptoms.
Molds are very common both inside and outside. There are many types, but only certain kinds of mold cause allergies. Being allergic to one type of mold doesn't necessarily mean you'll be allergic to another. Some of the most common molds that cause allergies include alternaria, aspergillus, cladosporium and penicillium.
When it's not an allergy
Although a mold allergy is the most common problem caused by exposure to mold, mold can cause illness without an allergic reaction. Mold can also cause infections or irritant and toxic reactions. Infections caused by mold can lead to a variety of problems from flu-like symptoms to skin infections and even pneumonia.
An irritant reaction is caused when substances from molds called volatile organic compounds irritate the mucous membranes in the body. Symptoms of an irritant reaction are similar to an allergy and include eye irritation, runny nose, cough, hoarseness, headache and skin irritation.
A toxic reaction to mold is a result of much exposure to substances called mycotoxins. As with an irritant reaction, the symptoms of a toxic reaction may also include flu-like symptoms, eye and skin irritation, and breathing troubles. You may also experience headaches, nervousness, dizziness, difficulty concentrating and extreme fatigue.
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